The role of Gamma Knife radiosurgery in arteriovenous malformation with aneurysms.

A review of 217 patients treated with Gamma knife radiosurgery (GKRS), at Hospital Na Homolce, Prague, between October 1992 and January 1998 for arteriovenous malformation (AVM) is presented. Forty-one patients (18.9%) with an AVM and associated aneurysm are the subjects of special interest for this study. The nidus volume in the presence of an aneurysm lying close to the nidus or within it was significantly larger than the nidus volume in cases where the AVMs had no associated aneurysm, suggesting that an increased flow in a larger AVM may be an important factor for aneurysm formation. The association of an arterial aneurysm with an AVM significantly increased the chance of hemorrhage when compared to the group with AVM and no aneurysm. Ten patients out of 14, who had an aneurysm close to or within the nidus, showed a complete obliteration of their AVM and aneurysm, although the latter was not always included within the irradiated volume. Thus, this study indicates that radiosurgery alone could be the method of choice for the treatment of a combination of AVM and aneurysm, if the aneurysm is close to or within the nidus.